1. Field of the Invention
The present invention relates to the flotation of ores, particularly to the flotation of minerals containing alkaline earth metal ions and oxidic copper and iron minerals, and more specifically to the use of certain synergistic mixtures of carboxylic acid compounds as collectors.
2. Description of the Prior Art
According to U.K. Pat. No. 1,355,091 a group of carboxylic acid derivatives containing a hydrophobic residue and having surfactant properties can be used as collectors for the flotation of various valuable constituents from ores. Although in many situations highly satisfactory results can be obtained with collectors of this large group of compounds, they have the common property that they possess a relatively strong tendency to foaming. This often causes an unfavorable influence on the desired separation during the flotation. Excessive frothing is a highly undesirable property in flotation practice. It results mostly into lower selectivities because gangue minerals are trapped in the tight froth structure. It is because of this difficulty that the superior activity and chemical selectivity of these compounds, compared with the usual fatty acid type collectors, cannot be utilized in practice to such an extent as would be desirable.
The collectors of the fatty acid type are old and well-known. These collectors usually contain oleic acid and are often called "oleic acid", even though some of the commercial collectors may only contain minor amounts of this particular acid. Of course, one will preferably use cheap materials for this purpose so that sure oleic acid is never used. Some usual materials are commercial oleic acid, oleic acid-containing wastes, fatty acids from tall oil, fatty acids from fish oils and the like. In the present specification and appending claims these materials will be called either "fatty acid type collectors", or "oleic acid-containing fatty acid type collectors", or simply "oleic acid".